This invention relates to spas, hot tubs, bathtubs and the like and, more particularly, to the use of an axial flow or turbine pump to circulate water under pressure to the spa jets and, further, to a cooling system used for cooling the electric motor driving the turbine pump.
The use of pumps in spas, hot tubs, bathtubs and the like is, of course, well known. Such pumps are used to receive water from a water inlet, place the water under pressure and convey such water to the various outlets or jets within the spa enclosure where the user is or is intended to be positioned. The water exiting the jets creates a flow within the water of the spa and exhausts on the user, if so desired. The water has a pleasant and therapeutic benefit.
The pumps that create the pressure and provide water to the jets within the spa, however, are centripetal type pumps. These pumps have an impeller with a central portion into which water from a water inlet is introduced. The impeller has a series of radially located vanes that conveys the water radially outwardly from the central inlet area to an outlet located adjacent the radial vanes. While such centripetal type pumps are pervasive in the industry, they have disadvantages.
A first disadvantage is that the water volume supplied under pressure by the centripetal type pump is limited. This dictates the size of jets that can be used in order to impinge properly upon a user and to create the desired currents within the tub. Second, with the use of a centripetal type pump, the operation is typically at the upper end of the pump volume capabilities. This causes high pump noise which is diversionary to the enjoyment of the spa. Thirdly, since the volume of water being pumped is limited, the jets may emit less water than would otherwise be desirable for optimum performance. Fourthly, to provide the necessary pressure on the user with the limited volume of water moved by the centripetal pump and exiting from the jets, the volume of water may need to be concentrated; that is, it is emitted from a smaller area. This narrow water jet then impinges over a limited area on the user which can make the spa use uncomfortable.
U.S. Pat. No. 5,647,736 (French) teaches a motor cooling technique typically used in spas. French takes air from within the component compartment of the spa and passes such air through the motor which powers the spa pump by using the cooling fan within the motor. French teaches collecting the hot air which has passed through the motor by an exhaust shroud and exhausting such air to ambient conditions outside the component compartment of the spa.
While the technique taught by the ""736 patent is generally satisfactory, advantages in such cooling techniques and increased flexibility in using the cooling air are possible. First, because French takes his cooling air from within the component compartment, which component compartment is the location of electrical and electronic components which generate heat, the air gathered from the component compartment by French is at a relatively elevated temperature which prejudices the motor cooling effect. Superior cooling with air at a lower temperature would be useful.
Second, by exhausting his collected and heated air to a location outside the spa, the thermal energy of the heated air dissipated in the atmosphere is wasted by French. It would be useful if the thermal energy of the heated air could be applied to other uses.
Third, motors used to power centripetal type pumps typically do not have wide operating environment capabilities. They are prone to overheating if used in adverse conditions such as high altitude, low humidity and high ambient temperature conditions. Likewise, if the ventilation surrounding the motor is poor such as would be the case when the pump and motor are located under the skirt of the spa, overheating and premature failure can result.
According to one aspect of the invention, there is provided water circulation apparatus for use in a water holding enclosure such as a spa, bathtub and the like, said apparatus comprising a water inlet, at least one water outlet operably connected to said water inlet and being operable to exhaust water under pressure passing from said water inlet to said water outlet and a pump for pumping said water received from said water inlet to said water outlet, said pump being an axial flow pump.
According to a further aspect of the invention, there is provided a method for providing water under pressure to at least one water outlet opening in a water holding enclosure such as a spa, bathtub and the like, said method comprising conveying said water under pressure from a water inlet to said water outlet opening by an axial flow pump located between said water inlet and said water outlet opening.
According to yet a further aspect of the invention, there is provided cooling apparatus for cooling the motor of a water pump, said motor having windings, said cooling apparatus comprising an air inlet member for obtaining cooling air from ambient surroundings and passing said cooling air to said motor, a duct to allow said cooling air to pass from said air inlet member to said motor, a fan within said motor to convey said cooling air from said duct through said motor and over said windings, an exhaust outlet in said motor to allow said cooling air to exhaust from said motor and at least one exhaust grid to allow said air conveyed from said exhaust outlet of said motor to exhaust to said ambient air.
According to still yet a further aspect of the invention, there is provided a method of cooling a motor used for driving a pump in a spa, bathtub and the like, said method comprising conveying cooling air from ambient surroundings through a duct to said motor, passing said cooling air from said duct through said motor, exhausting said cooling air from said motor and allowing said cooling air exhausted from said motor to exhaust from an air outlet grid to said ambient surroundings.
According to still yet a further aspect of the invention, there is provided a pump for pumping water in a spa, bathtub and the like, said pump being driven by a motor having an inside and an outside and windings, an air inlet to obtain cooling air from ambient surroundings, a duct to convey said cooling air to said motor, a fan to convey said cooling air over said windings, an exhaust outlet to exhaust said cooling air from said motor, and a shroud adjacent said exhaust outlet, said shroud being shaped to direct said cooling air back over said outside of said motor.
According to still yet a further aspect of the invention, there is provided a method for cooling a pump motor in a spa, bathtub and the like, said pump motor having an inside and an outside, said method comprising the steps of conveying cooling air from ambient surroundings through a duct to an air inlet of said pump motor, passing said cooling air through said inside of said motor, exhausting said cooling air from an exhaust opening in said pump motor and directing said cooling air back over said outside of said motor by a shroud located adjacent said exhaust opening of said pump motor.